This joint cooperative study of the natural history of ventricular septal defects, of valvar aortic stenosis, and valvar pulmonic stenosis is now in its seventh year. The objectives of the Study are: (1) to provide a means of predicting the clinical outlook for a patient with one of these lesions, (2) to provide criteria for surgical therapy, and (3) to provide reliable means of evaluating the degree of severity of the lesion without recourse to cardiac catheterization. Data collection is scheduled to be completed by November 30, 1973. Following that date, the phase of data analysis will commence. It is anticipated that to achieve the above mentioned objectives, a period of two years for this analysis, 1974 and 1975, will be required.